Fatty acid analysis of prehistoric burned rocks: a case study from central California

Although lipid analysis of archaeological residues has been utilized for almost three decades, it has rarely been applied to archaeological materials other than pottery. A 2001 study used lipid analysis of burned rocks (sandstone) and ground stone tools to interpret subsistence change at a south Texas site (M.J. Quigg, M.E. Malainey, R. Przybylski, G. Monks, No bones about it: using lipid analysis of burned rock and groundstone residues to examine Late Archaic subsistence practices in South Texas, Plains Anthropologist 46 (2001) 283-303). If such applications are reliable, insight into past subsistence practices could be greatly enhanced. The following study tested whether measurable amounts of lipids could be extracted from burned rocks (andesite) from a central California site and the ability of fatty acid analysis to reliably interpret those extracts. While results indicate that some of the burned rocks may contain lipids absorbed from cooking activities, lipids were also recovered from off-site rocks. Before reliable interpretations of culturally introduced lipids can be made, more thorough study of the types and amounts of lipids present in rocks due to natural processes is necessary.